The present invention relates to a pneumatic clutch suitable for a heavy automobile.
A conventional friction clutch for an automobile comprises complicated constructions such as clutch springs and a release mechanism constituted of releases lever, a release bearing, a shift fork and other mechanisms. Therefore, the conventional clutch has a heavy weight, and an especially long axial dimension when coil springs are employed as the clutch springs. Also, a master cylinder is required in an operating force transmitting mechanism connected to the shift fork, and a booster is also required in a heavy automobile, which also causes further complication of the construction and the increase of additional weight.
Further, wear of facings reduces pressure by the springs between the facings and the pressure plate. Therefore, an allowable value of the wear is rather small, and durability of the facings is short.
In a releasing operation of the clutch, the release bearing applies a force at the release levers or lever portions of a diaphragm spring. And the force applied toward a flywheel causes a remarkably large thrust, e.g., of 600 kg, in the engine side, therefore a thrust bearing having a large thrust capacity is required.
In order to change a maximum transmittable torque, it is necessary to change the clutch springs, which requires a long time and much labor.
Wear of the members causes unbalance of the pressure on the annular pressure plate, which results in jitter.
Accordingly it is an object of the invention to provide an improved pneumatic clutch suitable for a heavy automobile, overcoming the above-noted disadvantages.
Other and further objects, features and advantages of the invention will appear more fully from the following description of the preferred embodiments of the invention.